Within the group of disorders that comprise pulmonary arterial hypertension, PAH related to scleroderma (PAH-SSD) is associated with a high mortality and current therapy for patients with this disease is limited. Despite clinical and histologic similarities to idiopathic PAH (IPAH), distinct differences exist in proposed pathogenesis, response to therapy, and survival. For instance, the origin of the classic plexiform lesion in the pulmonary vasculature may differ between these two entities. Further, although both patients with IP AH and PAH-SSD respond to epoprostenoid therapy, the magnitude of response is more profound for patients with IP AH. Ultimately, survival for patients with PAH-SSD is much poorer than for patients with IP AH. Utilizing the large number of patients in our pulmonary hypertension registry at Johns Hopkins, we propose to prospectively study patients with PAH with the following specific aims: 1) to define prognostic factors for disease progression and survival in patients with PAH-SSD compared to patients with IP AH, 2) to identify candidate genes in PAH-SSD by disease-specific cDNA microarray analyses, and 3) to evaluate the effect of simvastatin therapy on clinical outcomes as assessed by exercise capacity, Borg dyspnea score, WHO/NYHA functional class, quality of life assessed by SF-36 survey, and time to clinical worsening in patients with PAH. [unreadable] [unreadable]